Air quality and respiratory disease in Newcastle, New South Wales.

OBJECTIVE: To investigate respiratory illnesses in the Newcastle region, their change over time, and their geographic relationship to industrialised areas. DESIGN: We analysed admissions to public hospitals by postcode area in the Newcastle region, for all causes and for all the various respiratory causes, for the years 1979-1988. Comparisons were made between the State of New South Wales and the Newcastle area, and between geographic areas within Newcastle. Changes over the 10-year period were noted. RESULTS: For both all causes and respiratory causes, admission rates to Newcastle hospitals, 1979-1988, were significantly lower than those for the rest of New South Wales in 1986. There was a correlation between living in the industrial part of the city and hospital admission for all causes and respiratory causes. There was also a correlation between mean disposable family income and hospital admissions, with those areas with the higher incomes having lower admission rates. Over the 10 years studied there was a statistically significant decline in admissions for respiratory causes, both in absolute terms and after controlling for changes in admissions for all causes. In children aged 0-14 years a significant increase in admissions for asthma occurred between 1979 and 1988, which could not be explained by diagnostic shift. CONCLUSIONS: On the basis of hospital statistics, the members of the Newcastle population seem little different from those in the remainder of New South Wales. From 1979-1988, the efforts by industry, with the support of the community, to reduce industrial pollution have been accompanied by a reduction in hospital admission rates for respiratory diseases in general and for chronic obstructive lung disease in older people. Other contributing factors include reduced smoking rates and improved medical management. Correlations between geographic location and respiratory admission rates may be a manifestation of social class rather than poor air quality, although a contribution from the latter cannot be discounted. A concomitant rise in asthma admission rates in children aged 0-14 is likely to be unrelated to any change in air quality.